Thanks a lot, sebaro and s_bernstein. "emerge -1" solved the problem. The problem I had was that the command I used was "emerge x11-base/xorg-drivers", which didn't actually force the rebuilding of those x11-drivers.

An aside: I found a way to test that without having to resort to the harmful and risky power-off button. I would start my laptop, then SSH into it from another machine and then "startx" within the SSH shell which would cause the XFCE session on the laptop to start. The advantage of this remote activation was that I could kill the XFCE session (Ctrl-C) from the remote shell and not subject my laptop to the really bad push the power-off button maneuver. Doing it this way is really compelling for performing emerge updates where there is a risk you might be frozen out of your machine. I guess one should having sshd auto start when rebooting after an emerge that affects X windows, XFCE or the likes.

which will rebuild all installed x11 drivers without futher interaction

+1

Great ! Thanks for your post, it has solved also my problem after an upgrade of nvidia-drivers. It could be nice if this tip was added in the post-install of the nvidia-drivers for those who have a problem of this kind.

which will rebuild all installed x11 drivers without futher interaction

Many thanks from me, too!

(I know this does not add information to this thread, but since it already has all needed information, the thank you should not hurt )_________________Being unpolitical means being political without realizing it. - Arne Babenhauserheide ( http://draketo.de )